Objective: Medicines with limited evidence of effectiveness are prime candidates for disinvestment. However, investment in further research may be preferable to de-implementation, given that the absence of evidence is not evidence of absence, and research can inform formulary decisions. A case in point is liothyronine, which is sometimes prescribed to levothyroxine-treated patients who continue to experience hypothyroid symptoms. It is a putative low value medicine, associated with uncertainties in both clinical and cost effectiveness. The aim was to assess the cost-effectiveness of liothyronine in this context, and estimate the value of conducting further research.
Design: Cost utility and value of information analyses.
Setting: Primary care within the National Health Service in the UK.
Participants: Fifty-four levothyroxine-treated patients with persistent symptoms of hypothyroidism.
Interventions: Liothyronine plus levothyroxine versus levothyroxine alone.
Primary and secondary outcome measures: Incremental cost per quality-adjusted life year (QALY) gained, and the expected monetary value of sample information.
Results: 20/54 (37%) of patients who responded to the survey reported severe problems in carrying out usual activities of everyday living and 12/54 (22%) reported severe anxiety or depression symptoms. Mean (SD) utility was 0.53 (0.23). The differences in expected total, 10-year costs and QALYs between a treatment strategy of liothyronine/levothyroxine combination therapy, and levothyroxine alone, was £12,053 and 1.014, respectively. The incremental cost effectiveness ratio of £11,881 per QALY gained was sensitive to the price of liothyronine. The probability of liothyronine/levothyroxine combination therapy being cost effective at a threshold of £20,000 per QALY was 0.56. The value of reducing uncertainty in the efficacy of treatment was £3.64m per year in the UK.
Conclusions: A definitive clinical trial to confirm clinical effectiveness may be preferable to immediate disinvestment, and would be justified given the value of the information gained far exceeds the cost.